Bi-amp ADS L1290/2

Discussion in 'General Audio Discussion' started by oldsmobuick, Sep 15, 2018.

  1. oldsmobuick

    oldsmobuick AK Subscriber Subscriber

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    Can I run full-bandwidth to the woofers and just build a couple 350Hz dividers into a box to run the signal from the preamp to the high signal outputs? Like the attached pic?

    Or do i low-pass the signal from the pre before sending to the woofers, or so i buy an outboard adjustable crossover instead of purpose-building?
     

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  2. oldsmobuick

    oldsmobuick AK Subscriber Subscriber

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    I see now the xo is at 500Hz on the 1290. Also that the high/mid still runs through the internal crossover so it can take full range input at the terminals. So really what I need to do is low-pass at 500Hz to the terminals of the woofers. Can any decent low-pass passive device be used here? I know ADS made one that say in the back cavity but it’s scarce.
     
  3. oldsmobuick

    oldsmobuick AK Subscriber Subscriber

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    Couple options maybe? Do I need to match any resistance values?
     

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  4. oldsmobuick

    oldsmobuick AK Subscriber Subscriber

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    Or I could use my spare XOs from a set of Klipsch Quartets. Those cross over the woofer at 650Hz.
     
  5. Dennis Gardner

    Dennis Gardner Jazz Nut

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    ADS has always used the biamp posts different than most models of speakers. Most speakers simply split the internal crossover into two parts so that they are still in use when biamping at the posts. ADS eliminates the internal induction coil within the bass circuit and replaced them with active units in the C2000 or in the amplifier made for the 90 series line that you have.

    There isn't anything wrong doing it the way you are looking at, and it is usually cheaper to approach it passively.
     
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  6. BigElCat

    BigElCat Mmm Hmm Subscriber

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  7. BigElCat

    BigElCat Mmm Hmm Subscriber

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  8. BigElCat

    BigElCat Mmm Hmm Subscriber

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    You'd almost have to wire each driver to it's own binding posts (both woofers could be on one set of posts).

    Then use an active, three way cross over, like from pro audio. Three amps.
     
  9. oldsmobuick

    oldsmobuick AK Subscriber Subscriber

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    Wow, that thread is serious. Thanks for linking! Maybe I’ll just feed them more power like you did and be happy.
     
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  10. BigElCat

    BigElCat Mmm Hmm Subscriber

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    You may wonder why ADS designed them like this.

    They had an external eq box designed for a different pair of speakers that allowed bi-amping using the internal x-over.

    They were apparently going to follow suit for the L1290s, then didn't do it. The other box could be re-engineered, but I don't remember the model number, and it's rare.
     
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